Vehicle headlamp

ABSTRACT

A vehicle headlamp, for projecting light forward along an optical axis extending in a longitudinal direction of the vehicle, is provided with a light source, a first main reflector, a second main reflector, a shade, and a projection lens. The light source emits light. The first main reflector is arranged above the light source and reflects the light emitted from the light source toward the optical axis. The second main reflector is arranged below the light source and reflects the light emitted from the light source toward a direction different from the optical axis. The shade cuts a part of the light reflected by the first main reflector to form a cut-of line. The projection lens is arranged in front of the first main reflector and forward projects the light having passed the shade.

The present application claims foreign priority based on Japanese PatentApplication No. P.2004-342742, filed on Nov. 26, 2004, the contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a large quantity of light type headlampfor use in a vehicle.

2. Related Art

There is a vehicle headlamp for projecting light ahead of the vehicleusing a projector type of lamp unit.

Such a projector type of lamp unit serves to forward collect/reflect thelight emitted from a light source, arranged in the vicinity on anoptical axis extending in a longitudinal direction of the vehicle,toward the optical axis by a reflector, and project the reflected lightahead of the lamp unit through a projection lens arranged in front ofthe reflector. When a distributed light pattern having a cut-off line onthe upper end is formed using this lamp unit, a shade is arranged in thevicinity of the focal point on the rear side of the projection lens anda part of the reflected light from the reflector is cut or shielded toform the cut-off line. (For example, JP-A-05-159603 discloses a vehicleheadlamp of this type.)

In recent years, as a vehicle headlamp equipped with the projector typelamp unit, its large quantity of light type thereof has been demanded.Generally, with respect to the light emitted from the light source,reflected by the reflector and incident on the projection lens, thevehicle headlamp equipped with the projector type lamp unit makeseffective light projected forward by the projection lens.

However, for example, the light which is incident on the lower side ofthe reflector and cut by the shade results in the lost light whichcannot contribute to distributed light to be projected forward. Further,the light which is not incident on the reflector but goes outwarddirectly from the light source or the light which is incident on thearea other than the reflector and makes diffused reflection within thelamp unit results in the lost light which cannot contribute todistributed light. Thus, the general projector type lamp unit makes alarge quantity of lost light which cannot contribute to the distributedlight to be projected forward. Therefore, effective use of this lostlight is demanded.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention provide a headlampwhich can reduce lost light incapable of contributing to distributedlight thereby to project a large quantity of light forward withoutchanging the output of a light source.

In accordance with one or more embodiments of the present invention, avehicle headlamp is provided with: an optical axis extending in alongitudinal direction of the vehicle; a light source for emittinglight; a first main reflector arranged above the light source, forreflecting the light emitted from the light source toward the opticalaxis; a second main reflector arranged below the light source, forreflecting the light emitted from the light source toward a directiondifferent from the optical axis; a shade for cutting a part of the lightreflected by the first main reflector to form a cut-off line; and aprojection lens arranged in front of the first main reflector, forforward projecting the light having passed the shade.

In addition, in accordance with one or more embodiments of the presentinvention, the vehicle headlamp may be further provided with: a firstsub-reflector arranged above the first main reflector, for forwardreflecting the light emitted from the light source.

In addition, in accordance with one or more embodiments of the presentinvention, the vehicle headlamp may be further provided with: a secondsub-reflector arranged above the second main reflector, for forwardreflecting the light emitted from the light source.

In addition, in accordance with one or more embodiments of the presentinvention, the vehicle headlamp may be further provided with: a thirdsub-reflector arranged on at least one of the forward right side andforward left side of the first main reflector, for rearward reflectingthe light emitted from the light source; and a fourth sub-reflector forforward reflecting the light reflected by the third sub-reflector.

In addition, in accordance with one or more embodiments of the presentinvention, the vehicle headlamp may be further provided with: a fifthsub-reflector arranged in front of the first main reflector, fordownward reflecting the light emitted from the light source; and a sixthsub-reflector for forward reflecting the light reflected by the fifthsub-reflector.

According to the one or more embodiments of the present invention, sincethe second main reflector and the first to sixth sub-reflectors arearranged around the first main reflector, the light not projectedforward as the lost light in the conventional projector type vehicleheadlamp can be projected as effective light forward of the vehicle.Thus, without improving the output of the light source, the output ofthe vehicle headlamp can be increased, thereby providing a largequantity of light type vehicle headlamp.

Moreover, since projected areas of the second main reflector and firstto sixth sub-reflectors are set in various manners, the light can beprojected to the side not illuminated by only the first main reflector,thereby enhancing side visibility; or otherwise the light quantity atthe center of the distributed pattern can be increased, therebyenhancing far distance visibility.

Other aspects and advantages of the invention will be apparent from thefollowing description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the overall appearance of a vehicleheadlamp.

FIG. 2 is a top view of the vehicle headlamp.

FIG. 3 is a front view of the vehicle headlamp.

FIG. 4 is a side view of the vehicle headlamp.

FIG. 5 is a sectional view taken in line V-V in FIG. 2.

FIG. 6 is a sectional view taken in line VI-VI in FIG. 3.

FIG. 7 is a front view of the shade attached to the vehicle headlamp.

FIG. 8 is an optical path diagram in which rays of light are describedin FIG. 5.

FIG. 9 is an optical path diagram in which rays of light are describedin FIG. 6.

FIG. 10 is a schematic diagram showing distributed light patterns formedby the vehicle.

REFERENCE NUMERALS AND CHARACTERS

Note, in the drawings, the reference numeral 10 is a vehicle headlamp;20 is a lamp unit; 22 is a light source bulb; 22 a is a light source; 24is a first main reflector; 26 is a second main reflector; 28 is a shade;29 is a projection lens; 31 is a first sub-reflector; 32 is a secondsub-reflector; 33 is a right third sub-reflector; 34 is a right fourthsub-reflector; 35 is a left third sub-reflector; 36 is a left fourthsub-reflector; 37 is a fifth sub-reflector; and 38 is a sixthsub-reflector, and the character Ax is an optical axis.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will be described with reference to theaccompanying drawings.

FIG. 1 is a perspective view of the overall appearance of a vehicleheadlamp according to an embodiment of the present invention. FIG. 2 isa top view of the vehicle headlamp according to the embodiment of thepresent invention. FIG. 3 is a front view of the vehicle headlampaccording to the embodiment of the present invention. FIG. 4 is a sideview of the vehicle headlamp according to the embodiment of the presentinvention. FIG. 5 is a sectional view taken in line V-V in FIG. 2. FIG.6 is a sectional view taken in line VI-VI in FIG. 3. FIG. 7 is a frontview of the shade attached to the vehicle headlamp according to theembodiment of the present invention. Incidentally, in FIGS. 1 to 4, theshape of unseen members hidden by the members on the forward side areindicated in broken line.

A vehicle headlamp 10 according to this embodiment is arranged as a lampunit 20 within a lamp chamber formed by a lamp body (not shown) and alight permeable cover attached to cover a front opening of the lampbody.

The lamp unit 20 is a projector type lamp unit provided with pluralreflecting members. As shown in FIGS. 1 to 6, the lamp unit 20 includesa first main reflector 24 and a second main reflector 26 which aredivided upper and lower parts, and first to sixth sub-reflectors 31 to38 arranged around the first main reflector 24 and second main reflector26.

First, the first main reflector 24 will be explained.

The first main reflector 24, as seen from FIG. 5, is a reflecting memberhaving a reflecting face 24 a on the inside and forward projecting lightwhich serves as main distributed light of the vehicle use lamp 10. Thereflecting face 24 a has a substantially elliptical shape contributingto light condensing as a vertical sectional shape and a free curvedshape contributing to light diffusion in the width direction as ahorizontal sectional shape. The first main reflector 24 corresponds toan upper half part which is horizontally cut below the central axis ofthe reflecting face 24 a, and forms a semi-domed shape.

The first main reflector 24 has an opening 24 b formed on the rear sidealong the central axis of the reflecting face 24 a. A light source bulb22 is firmly inserted in the opening 24 b in parallel to the centralaxis of the reflecting face 24 a from the rear side of the mainreflector 24. Thus, the first main reflector 24 is attached to cover thetop and side of the light source bulb 22. Incidentally, in thisembodiment, the first main reflector 24 is arranged so that the centralaxis of the reflecting face 24 a constitutes an optical axis Ax of thevehicle headlamp 10 which extends in the longitudinal direction of thevehicle. A front side opening edge 24 c of the first main reflector 24is oriented to the forward side of the vehicle (see FIG. 6).

The light source bulb 22 may be a discharge bulb such as a metal halidebulb. Light is emitted from a light source 22 a which is constructed ofa discharging/emitting portion of the discharge bulb. The light sourcebulb 22 is arranged in the vicinity of a first focal point P1 of thefirst main reflector 24 arranged on the optical axis Ax. The light whichis emitted from the light source bulb 22 and incident on the reflectingface 24 a of the first main reflector 24 is reflected toward a secondfocal point P2 of the first main reflector 24 which is also arranged onthe optical axis Ax.

On the forward side in the optical axis direction of the first mainreflector 24, a shade 28 and a projection lens 29 are arranged.

The shade 28 is a cutting member for cutting a part of the light whichis emitted from the light source 22 a of the light source bulb 22 andreflected by the reflecting face 24 a of the first main reflector 24.The upper edge 28 a is arranged at a position slightly behind the secondfocal point of the first main reflector 24 in the longitudinal directionof the vehicle so that the longitudinal direction of the shade 28 isorthogonal to the optical axis Ax. The upper edge 28 a of the shade 28has a shape corresponding to a distributed light pattern projectedforward so that a part of the light going toward the second focal pointP2 is cut according to the shape of the upper edge 28 a.

The projection lens 29 is a convex lens arranged in front of the shade28, which has a convex portion 29 a formed on the front side and a flatincident face 29 b formed on the rear side so as to be vertical to theoptical axis Ax. The rear focal point of the projection lens 29 islocated in vicinity of the second focal point of the first mainreflector 24. The projection lens 29 forward projects, as nearlyparallel rays of light, the light from the first main reflector 24 whichhas not been cut by the shade 28 but passed the shade 28.

Next, the second main reflector 26 will be explained below.

The second main reflector 26 is a reflecting member arranged below thefirst main reflector 24 and having a reflecting face 26 a on the inside.The reflecting face 26 a has a substantially parabolic shape as avertical sectional shape and a free curved shape contributing to lightdiffusion in the width direction as a horizontal sectional shape. Thesecond main reflector 26 corresponds to a lower half part which ishorizontally cut below the central axis of the reflecting face 26 a, andforms a semi-domed shape. The central axis of the reflecting face 26 aof the second main reflector 26 is located to form a certain angle withthe reflecting face 24 a of the first main reflector 24. Thus, thesecond main reflector 26 has an opening edge 26 b oriented aslantrightward on the forward side of the vehicle (see FIG. 6).

The second main reflector 26 is located below the light source 22 a, andthe focal point of the second main reflector 26 is located so as tosubstantially agree with the light source 22 a of the light source bulb22. Thus, the second main reflector 26 forward reflects the lightemitted from the light source 22 a by the reflecting face 26 a. Now, infront of an opening edge 26 b of the second main reflector 26, the shade28 is arranged. And, as seen from FIG. 7, the shade 28 has a recess 28 bformed not to cut the light from the second main reflector 26. The lightreflected by the reflecting face 26 a of the second main reflector 26 isprojected forward through the recess 28 b.

Next, the first to sixth sub-reflectors 31 to 38 will be explained insequence.

The first sub-reflector 31 is a reflecting member arranged above thefirst main reflector 24 and equipped with a reflecting face 31 a havinga substantially parabolic shape as a vertical sectional shape and a freecurved shape contributing to light diffusion in the width direction as ahorizontal sectional shape. The reflecting face 31 a of the firstsub-reflector 31 is located so that its focal point substantially agreeswith the light source 22 a, and forward reflects the light emittedaslant upward on the forward side from the light source 22 a, which isprojected forward as nearly parallel rays of light. As seen from FIGS. 1and 2, the first main reflector 24 located between the firstsub-reflector 31 and the light source 22 a has a recess 24 d formed notto hinder the incidence of light on the first sub-reflector 31 from thelight source 22 a. The light emitted from the light source 24 a isincident on the first sub-reflector 31 through the recess 24 d.

The second sub-reflector 32 is a reflecting member arranged below thefirst main reflector 24 and equipped with a reflecting face 32 a havinga substantially parabolic shape as a vertical sectional shape and a freecurved shape contributing to light diffusion in the width direction as ahorizontal sectional shape. The reflecting face 32 a of the secondsub-reflector 32 is located so that its focal point substantially agreeswith the light source 22 a, and forward reflects, as nearly parallelrays of light, the light emitted aslant downward on the forward sidefrom the light source 22 a. As seen from FIG. 4, the second mainreflector 26 located between the second sub-reflector 32 and the lightsource 22 a has a recess 26 c formed not to hinder the incidence oflight on the second sub-reflector 32 from the light source 22 a. Thelight emitted from the light source 24 a is incident on the secondsub-reflector 32 through the recess 26 c.

The right third sub-reflector 33 is a reflecting member arranged on theforward right side of the first main reflector 24 and equipped with areflecting face 33 a having a substantially rotary elliptical shape. Thereflecting face 33 a of the right third sub-reflector 33 is located sothat its focal point substantially agrees with the light source 22 a,and rearward reflects the light emitted rightward on the forward sidefrom the light source 22 a.

The right fourth sub-reflector 34 is a reflecting member arrangedright-aside of the first main reflector 24 and equipped with areflecting face 34 a having a substantially parabolic shape as avertical sectional shape and a free curved shape contributing to lightdiffusion in the width direction as a horizontal sectional shape. Thereflecting face 34 a of the right third sub-reflector 34 is located sothat its focal point substantially agrees with the second focal point P3of the right third sub-reflector 33, and reflects the light incidentfrom the reflecting face 33 a of the right third sub-reflector 33, whichis projected forward as nearly parallel rays of light.

The left third sub-reflector 35 is a reflecting member arranged on theforward left side of the first main reflector 24 and equipped with areflecting face 35 a having a substantially rotary elliptical shape. Thereflecting face 35 a of the left third sub-reflector 35 is located sothat its focal point substantially agrees with the light source 22 a,and reflects the light emitted leftward on the forward side from thelight source 22 a toward the vicinity of the second focal point P4 onthe rearward side.

The left fourth sub-reflector 36 is a reflecting member arrangedleft-aside of the first main reflector 24 and equipped with a reflectingface 36 a having a substantially parabolic shape as a vertical sectionalshape and a free curved shape contributing to light diffusion in thewidth direction as a horizontal sectional shape. The reflecting face 36a of the left fourth sub-reflector 36 is located so that its focal pointsubstantially agrees with the second focal point P4 of the left thirdsub-reflector 35, and reflects the light incident from the reflectingface 35 a of the left third sub-reflector 35, which is projected forwardas nearly parallel rays of light.

Incidentally, the optical system formed by the right third sub-reflector33 and the right fourth sub-reflector 34 and the optical system formedby the left third sub-reflector 35 and the left fourth sub-reflector 36are different in their left and right locating positions and projectingregions, but their basic arrangements are equivalent except for thedifference in their left and right arranging positions. Therefore, inthis specification, the right third sub-reflector 33 and left thirdsub-reflector 35 are generally termed “third sub-reflector” and the leftthird sub-reflector 34 and left fourth sub-reflector 36 are generallytermed “fourth sub-reflector”.

The fifth sub-reflector 37 is a reflecting member arranged below thefirst sub-reflector 31 and extended to the top of the opening edge 24 con the forward side of the first main reflector 24, and having areflecting face 37 of a substantially rotary elliptical shape. Thereflecting face 37 a of the fifth sub-reflector 37 is located so thatits first focal point substantially agrees with the light source 22 a,and reflects the light emitted upward on the forward side from the lightsource 22 a toward the vicinity of the second focal point P5 locatedbelow.

The sixth sub-reflector 38 is a reflecting member arranged in front ofthe second main reflector 26 and equipped with a reflecting face 38 ahaving a substantially parabolic shape as a vertical sectional shape anda free curved shape contributing to light diffusion in the widthdirection as a horizontal sectional shape. The reflecting face 38 a ofthe sixth sub-reflector 38 is located so that its focal pointsubstantially agrees with the second focal point P5 of the fifthsub-reflector 37 and reflects the light incident from the reflectingface 38 a of the sixth sub-reflector 38 which is projected forward. Thecentral axis of the reflecting face 38 a of the sixth sub-reflector 38is located to form a certain angle with the optical axis Ax so that thelight reflected from the reflecting face 38 a its projected aslantsideward on the forward side of the vehicle.

Next, referring to FIGS. 8 to 10, a concrete explanation will be givenof the optical path through the first main reflector 24, second mainreflector 26 and first to sixth sub-reflectors 31 to 38 and adistributed light pattern projected.

FIG. 8 is an optical path diagram in which rays of light are describedin FIG. 5. FIG. 9 is an optical path diagram in which rays of light aredescribed in FIG. 6. FIG. 10 is a schematic diagram showing distributedlight patterns formed by the vehicle headlamp according to thisembodiment.

First, an explanation will be given on the first main reflector 26.

As seen from FIGS. 8 and 9, the light which is emitted from the lightsource 22 a and incident on the first main reflector 24 is reflectedtoward the optical axis Ax by the reflecting face 24 a of the first mainreflector 24 and collected at the vicinity of the second focal point P2of the first main reflector 24. Now, a part of the reflected light iscut according to the shape of the upper edge 28 a of the shade 28, andthe light not cut is incident on the projection lens 29 through thevicinity of the second focal point P2. The light made as parallel raysof light by the projection lens 29 is projected forward.

As seen from FIG. 10, the light projected forward via the first mainreflector 24 forms a basic distributed light pattern 101 with a cut-offline 102 on the upper end. The cut-off line 102 has a shape formed whenthe shape of the upper edge of the shade 28 is inverted upside down andleft and right. In this embodiment, the horizontal line 102 a on theleft side in the forward direction of the vehicle is connected to thehorizontal line 102 b on the right side in the forward direction of thevehicle by a slope 102 c. The horizontal line 102 a is located at ahigher position than the horizontal line 102 b in their horizontalheight.

Next, an explanation will be given on the second main reflector 26.

As seen from FIGS. 8 and 9, the light which is emitted from the lightsource 22 a and incident on the second main reflector 26 is reflectedtoward the direction inclined rightward in the forward direction of thevehicle from the optical axis Ax by the reflecting face 26 a of thesecond main reflector 26. The reflected light passes below the shade 28and is projected forward as rays of light (indicated by broken line inFIG. 9).

As seen from FIG. 10, the light projected forward via the second mainreflector 26 forms a first auxiliary distributed light pattern 103 whichilluminates a side region (right region in FIG. 10) not illuminated bythe basic distributed light pattern 101. This first auxiliarydistributed light pattern 103 gives an advantage of increasing thebrightness of the side region to improve the side visibility of thevehicle.

Generally, in the projector type of vehicle headlamp equipped with areflector having a semi-elliptical spherical shape, the light incidenton the lower half part of the reflector located at the position of thesecond main reflector 26 will be cut by the shade 28, and hence cannotbe taken out as effective light. However, according to this embodiment,the central axis of the second main reflector 26 is located in adirection inclined from that of the first main reflector 24 so that thelight collected in a different direction is projected. Thus, the lightcan be projected forward as the effective light.

Next, an explanation will be given on the first sub-reflector 31.

As seen from FIG. 8, the light emitted upward on the forward side of thevehicle from the light source 22 a is incident on the firstsub-reflector 31 and reflected by the reflecting face 31 a of the firstsub-reflector 31. The reflected light is projected forward as nearlyparallel rays of light. As seen from FIG. 10, the light projectedforward via the first sub-reflector 31 is superposed on the basicdistributed light pattern 101 to form a second auxiliary distributedlight pattern 104 which increases the light intensity of the area(so-called hot zone) beneath the cut-off line 102 and in the vicinity ofthe center of the basic distributed pattern 101. This second auxiliarydistributed light pattern 104 can increase the far distance visibilityby increasing the light intensity of the hot zone of the basicdistributed light pattern 101.

Next, an explanation will be given on the second sub-reflector 32.

As seen from FIG. 8, the light emitted downward on the forward side ofthe vehicle from the light source 22 a is incident on the secondsub-reflector 32 and reflected by the reflecting face 32 a of the secondsub-reflector 32. The reflected light is projected forward as parallelrays of light. As seen from FIG. 10, the light projected forward via thesecond sub-reflector 32 is superposed on the basic distributed lightpattern 101 to form the second auxiliary distributed light pattern 104which increases the light intensity of the area (so-called hot zone) inthe vicinity of the center of the basic distributed pattern 101. Thus,the second sub-reflector 32 contributes to illuminate the same area asthat for the first sub-reflector 31.

In the general projector type of vehicle headlamp, the end of the mainreflector is often extended into an area where the first sub-reflector31 and the second sub-reflector 32 are arranged. In this case, the lightreflected to the vicinity of the end of the main reflector is difficultto be projected forward through the projection lens. In many case, thereflected light is not projected but results in the light scatteredwithin the lamp unit. On the other hand, in accordance with thisembodiment, such light is collected by the first sub-reflector 31 andthe second sub-reflector 32 so that it is projected forward. Thus, thelight emitted from the light source 22 a can be effectively used aseffective light.

Next, an explanation will be given on the right third sub-reflector 33and right fourth sub-reflector 34 and the left third sub-reflector 35and left fourth sub-reflector 36.

As seen from FIG. 9, the light emitted rightward on the forward side ofthe vehicle from the light source 22 a is reflected rearward by theright third sub-reflector 33, and is incident on the right fourthsub-reflector 34 via the vicinity of the second focal point P3 of theright third sub-reflector 33. The light is reflected by the right fourthsub-reflector 34 so that it is projected forward nearly as parallel raysof light.

Likewise, the light emitted leftward on the forward side of the vehiclefrom the light source 22 a is reflected rearward by the left thirdsub-reflector 35, and is incident on the left fourth sub-reflector 36via the vicinity of the second focal point P4 of the left thirdsub-reflector 35. The light is reflected by the left fourthsub-reflector 36 so that it is projected forward nearly as parallel raysof light.

As seen from FIG. 10, the light projected forward via these right fourthsub-reflector 34 and left fourth sub-reflector 36 is superposed on thebasic distributed light pattern 101 to form the second auxiliarydistributed light pattern 104 which increases the light intensity of thearea (so-called hot zone) in the vicinity of the center of the basicdistributed pattern 101. Thus, the right fourth sub-reflector 34 and theleft fourth sub-reflector 36 contribute to illuminate the same areas asthat for the first and second sub-reflectors 31 and 32.

In the general projector type of vehicle headlamp, a lens holder isoften provided in the area where the right third sub-reflector 33 andleft third sub-reflector 35 are arranged. In this case, in many cases,the light incident on the inner periphery of the lens holder is notprojected forward but results in the light scattered within the lampunit.

On the other hand, in accordance with this embodiment, such light isreflected rearward by the right third sub-reflector 33 and left thirdsub-reflector 35 and further reflected by the right fourth sub-reflector34 and left fourth sub-reflector 36 so that it is forward collected andprojected. Thus, the light emitted from the light source 22 a can beeffectively used as effective light.

Next, an explanation will be given on the fifth sub-reflector 37 and thesix sub-reflector 38.

As seen from FIG. 8, the light emitted upward on the forward side of thevehicle from the light source 22 a is reflected downward by the fifthsub-reflector 37. The light is incident on the sixth sub-reflector 38via the vicinity of the second focal point P5 of the fifth sub-reflector37 and reflected by the sixth sub-reflector 38. The light reflected fromthe reflecting face 38 a of the sixth sub-reflector 38 is projectedaslant sideward on the forward side of the vehicle.

As seen from FIG. 10, the light projected forward via the fifthsub-reflector 37 and sixth sub-reflector 38 forms a third auxiliarydistributed light pattern 105 overlapping both the basic distributedlight pattern 101 and first auxiliary distributed light pattern 103. Thethird auxiliary distributed light pattern 105 illuminates the side ofthe basic distributed light pattern 101 to improve the side visibilityand continuously connect the basic distributed light pattern 101 andfirst auxiliary distributed light pattern 103 so that a dark zone is notformed between the basic distributed light pattern 101 and the firstdistributed light pattern 103.

In the general projector type of vehicle headlamp, the lens holder isoften provided in the area where the fifth sub-reflector 37 is arranged.In this case, in many cases, the light incident on the inner peripheryof the lens holder is not projected forward but results in the lightscattered within the lamp unit. On the other hand, in accordance withthis embodiment, such light is reflected downward by the fifthsub-reflector 37 and then reflected by the sixth sub-reflector 38 sothat it is forward collected and projected. Thus, the light emitted fromthe light source 22 a can be effectively used as effective light.

As described above, in the vehicle headlamp 10 according to thisembodiment, the second main reflector 26 and plural sub-reflectors 31 to38 are arranged around the first main reflector 24. In accordance withsuch a configuration, the light not projected forward as the lost lightin the conventional projector type vehicle headlamp can be projected aseffective light on the forward side of the vehicle. Thus, withoutimproving the output of the light source 22 a, the output of the vehicleheadlamp can be increased, thereby providing a large light quantity typeof vehicle headlamp.

Incidentally, in this embodiment, the second main reflector 26 projectslight right-sideward to form the first auxiliary distributed lightpattern 103; the first to left fourth sub-reflectors 31 to 36 projectlight forward of the vehicle to form the second auxiliary distributedlight pattern 104; and the fifth to sixth sub-reflectors 37, 38 projectlight between the first auxiliary distributed light pattern 103 andsecond auxiliary light distributed light pattern 104 to form the thirdauxiliary distributed light pattern 105. However, the manner of formingthe distributed light patterns should not be limited to this embodiment,but according to an objective distributed light pattern, the lightprojecting directions of the second main reflector 26 and first to sixthsub-reflectors 31 to 38 may be changed as required.

Further, in this embodiment, the second main reflector 26 and first tosixth sub-reflectors 31 to 38 project light forward not through theprojection lens. However, without being limited to such a configuration,by forming all the reflecting faces in an elliptical shape and arrangingthe shade and projection lens so as to correspond to the single focalpoint of the elliptical shape, the auxiliary distributed light patternhaving the cut-off line may be projected forward.

Further, in this embodiment, the second main reflector 26 and first tosixth sub-reflectors 31 to 38 are fixed. However, without being limitedto such a configuration, the orientation of the reflecting faces may bechanged by various driving mechanisms so that the zone to be illuminatedchanged is changed as circumstances demand.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the described preferredembodiments of the present invention without departing from the spiritor scope of the invention. Thus, it is intended that the presentinvention cover all modifications and variations of this inventionconsistent with the scope of the appended claims and their equivalents.

1. A vehicle headlamp comprising: an optical axis extending in alongitudinal direction of the vehicle; a light source for emittinglight; a first main reflector arranged above the light source, forreflecting the light emitted from the light source toward the opticalaxis; a second main reflector arranged below the light source, forreflecting the light emitted from the light source toward a directiondifferent from the optical axis; a shade for cutting a part of the lightreflected by the first main reflector to form a cut-off line; and aprojection lens arranged in front of the first main reflector, forforward projecting the light having passed the shade.
 2. The vehicleheadlamp according to claim 1, further comprising: a first sub-reflectorarranged above the first main reflector, for forward reflecting thelight emitted from the light source.
 3. The vehicle headlamp accordingto claim 1, further comprising: a second sub-reflector arranged abovethe second main reflector, for forward reflecting the light emitted fromthe light source.
 4. The vehicle headlamp according to claim 1, furthercomprising: a third sub-reflector arranged on at least one of theforward right side and forward left side of the first main reflector,for rearward reflecting the light emitted from the light source; and afourth sub-reflector for forward reflecting the light reflected by thethird sub-reflector.
 5. The vehicle headlamp according to claim 1,further comprising: a fifth sub-reflector arranged in front of the firstmain reflector, for downward reflecting the light emitted from the lightsource; and a sixth sub-reflector for forward reflecting the lightreflected by the fifth sub-reflector.
 6. The vehicle headlamp accordingto claim 1, further comprising: a first sub-reflector arranged above thefirst main reflector, for forward reflecting the light emitted from thelight source; a second sub-reflector arranged above the second mainreflector, for forward reflecting the light emitted from the lightsource; a third sub-reflector arranged on at least one of the forwardright side and forward left side of the first main reflector, forrearward reflecting the light emitted from the light source; a fourthsub-reflector for forward reflecting the light reflected by the thirdsub-reflector; a fifth sub-reflector arranged in front of the first mainreflector, for downward reflecting the light emitted from the lightsource; and a sixth sub-reflector for forward reflecting the lightreflected by the fifth sub-reflector.
 7. The vehicle headlamp accordingto claim 6, wherein the first main reflector includes a reflecting facewith a substantially elliptical shape as a vertical sectional shape anda free curved shape as a horizontal sectional shape; the light source isarranged in vicinity of a first focal point of the first main reflector;the light emitted from the light source and incident on the reflectingface of the first main reflector is reflected toward a second focalpoint of the first main reflector; the rear focal point of theprojection lens is located in vicinity of the second focal point of thefirst main reflector; the second main reflector includes a reflectingface with a substantially parabolic shape as a vertical sectional shapeand a free curved shape as a horizontal sectional shape. the firstsub-reflector includes a reflecting face having a substantiallyparabolic shape as a vertical sectional shape and a free curved shape asa horizontal sectional shape; the second sub-reflector includes areflecting face having a substantially parabolic shape as a verticalsectional shape and a free curved shape as a horizontal sectional shape;the third sub-reflector includes a reflecting face having asubstantially rotary elliptical shape; the fourth sub-reflector includesa reflecting face having a substantially parabolic shape as a verticalsectional shape and a free curved shape as a horizontal sectional shape;the fifth sub-reflector includes a reflecting face of a substantiallyrotary elliptical shape; and the sixth sub-reflector includes areflecting face having a substantially parabolic shape as a verticalsectional shape and a free curved shape as a horizontal sectional shape.